1. Field of the Invention
The present invention relates to an image forming apparatus and a photoreceptor cartridge usable in such an image forming apparatus.
2. Description of the Related Art
The image forming apparatus including a facsimile machine, a printer, a scanner and a multifunction machine is a kind of office equipment that is widely used in daily office work. Such an image forming apparatus forms an image by using a photoreceptor cartridge, and if the toner in the photoreceptor cartridge runs out, it is necessary to replace the photoreceptor cartridge in time so as to ensure normal operation of the image forming apparatus; on the other hand, if the image forming apparatus is to be maintained, it is often necessary to remove or insert the photoreceptor cartridge.
The photoreceptor cartridge is usually removed from or inserted into the image forming apparatus by riding on two guide axles. In order to prevent mis-insertion of the photoreceptor cartridge in the process of insertion of the photoreceptor cartridge, it is common to use a method in which a guide axle first inserted into the image forming apparatus is formed thicker than a guide axle subsequently inserted of the two guide axles on the photoreceptor cartridge, and a guide groove corresponding to the guide axle first inserted (hereinafter referred to as “first insert guide groove”) is formed thicker than a guide groove corresponding to the guide axle subsequently inserted (hereinafter referred to as “subsequently insert guide groove”) in the image forming apparatus. That is to say, both of the guide axle subsequently inserted into the image forming apparatus and the subsequently insert guide groove corresponding thereto are relatively thin; therefore, this method is capable of preventing mis-insertion in the process of insertion of the photoreceptor.
Furthermore, there is another method for preventing the mis-insertion of the photoreceptor cartridge, and more concretely, in this method a projection part is provided near the guide axle first inserted, and the projection part has a larger diameter than the guide axle subsequently inserted, so that, it is capable of preventing mis-insertion of the photoreceptor.
However, the above-mentioned two methods can prevent only mis-insertion of the guide axle first inserted of the photoreceptor cartridge, and cannot effectively prevent mis-insertion of the guide axle subsequently inserted. The reason for this is that in the above-mentioned two methods, the first insert guide groove opened on the image forming apparatus is relatively thick and the subsequently insert guide groove is relatively thin, so that the guide axle for subsequent insertion may be inserted into the guide groove for first insertion, causing mis-insertion. In this case, it is necessary to perform a secondary operation to correct the mis-insertion, that is, to remove the photoreceptor and insert it again.
In this way, the operation of insertion becomes complex, the operation becomes inefficient, and the operability becomes worse. On the other hand, it is often necessary to push the photoreceptor into the image forming apparatus with a certain acting force when the photoreceptor cartridge is inserted; therefore, if a mis-insertion takes place in the process of the insertion and an acting force is applied accidentally, it may be easy to cause a break in or damage to the guide axle, or even to the photoreceptor cartridge.